Part 11- Proteins and Protein Synthesis Flashcards
Are envelope proteins energy-dependent or energy-independent?
Energy-dependent
Hydrolysis of GTP to GDP
What do envelope proteins fuse to?
Fusion with the target membrane
How do we classify the vesicles?
With the coating proteins on the surface
What are two examples of hormone receptors?
Insulin and Glucagon
What are two examples of transport proteins?
GLUT 2 and NA-K ATPase
Vesicles that come from the Golgi apparatus and go to the plasma membrane are always coated with what vesicle?
Clathrin
What is the name of the envelope proteins that come from the ER to the Golgi apparatus?
COP 1 or COP 2
Where is Synaptobrevin located?
Localized on the surface of synaptic vesicles
What is the responsibility of Synaptobrevin?
Responsible for fusion of synaptic vesicles with the plasma membrane
What is the nuclear membrane associated with?
With the rER membrane
Where is the nuclear transport signal (NLS) located?
located in the middle of the polypeptide chain
How is the nuclear transport signal made?
Made from basic amino acids from a minimum of 5
e.g. -Pro-Lys-Lys-Lys-Arg-Lys-Val
What is the receptor of the nuclear transport signal?
Importin (2 SU)
T or F:
The nuclear transport signal goes to the ER.
FALSE:
it will never go to the ER (because they are internal signals)
Where does the nuclear transport signal get synthesized?
Synthesized in the “free” ribosomes in the cytosol
Do ALL proteins determined for the nucleus be actively transported/translocated?
YES
e.g., Histones, Transcription factors, Polymerase, etc
What does the Golgi apparatus consists of?
cis-Golgi, medial-Golgi, trans-Golgi
Where does the modification of the N-attached sugar chains of glycoproteins take place?
A. medial-Golgi
B. cis-Golgi
C. trans-Golgi
medial-Golgi
Where does protein phosphorylation take place?
A. medial-Golgi
B. cis-Golgi
C. trans-Golgi
cis-Golgi
Where does the the packing of proteins in vesicles and sent to the specific “delivery address” take place?
trans-Golgi
What are the characteristics of chaperons in protein folding?
A. they are ATPases
B. they have high activity at high temperatures
C. they are heat-stable proteins
D. all of the above
E. none of the above
D. All of the above
What does the folding cyclus require?
ATP
What does the chaperon bind to?
ADP
What happens if a protein is not correctly folded?
It will NOT leave the ER
Does the ADP/Chaperon-complex have a high or low affinity for unfolded proteins?
HIGH affinity
Where does O-Glycosylation start?
in Golgi apparatus
*(it’s O and golgi has an O in it)
What does the O-Glycosylation attach to?
Attachment of a sugar chain to an -OH group of Ser or Thr
*O also stands for hydroxyl group (-OH)
What is O-Glycosylation important for?
A. Important for the hydrolysis of GTP to GDP
B. Helps with the binding of ADP/chaperon complex
C. Important for the functional conformation of a protein
D. Fusion of synaptic vesicles with the ER
C. Important for the functional conformation of a protein
What are the sugar chains in protein important for?
Sorting and function of a protein
Where does N-Glycosylation start in?
Starts in ER
What does N-Glycosylation attach to?
Attachment of a sugar to an animo group of asparagine (Asn)
*N for amiNo
What is the N-Glycosylation recognition sequence? A. Pro-Val-Ser/Thr B. Asn-X-Ser/Thr C. Lys-X-Ser/Thr D. Pro-Lys-Ser/Thr
B. Asn-X-Ser/Thr
X: amino group
What are two examples of signal proteins?
G-Proteins and adenylyl cyclase
